Paper-pulp mold



(No Model.)

, G..]E. SPBER. PaperPulpMold.

No.' 235,585; Patented Dea-14, |880.

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PAPER-PULP MOLD.

SPECIFICATION formingpart of Letters Patent No. 235,585, dated December 14, 1880.

Application iiled November 16, 1880.

To all whom it may concern:

Be it known Jthat I, GARRETT F. SPEER, of the city and county of Philadelphia, and State of Pennsylvania, have invented certain new and useful Improvements in Paper-Pulp Molds; and I do hereby declare that the following is a full, clear, and exact description of the invention, which will enable others skilled in the art to which it appertains to malte and use the same, reference being had to the accompanying' drawings, and to letters of reference marked thereon, which form a part of this specification.

Figure l is a vertical central cross-section of the mold ready for the reception of the pulp. Fig. 2 is a similar section of the mold filled, with the plunger inserted. Fig. 3 is a perspective view of the disk withdrawn from the mold, and having the perforated flexible springband partially removed. Fig. 4 is a separate perspective View of the flexible strip.

The same letter marks the same part in the several figures where it occurs.

My invention relates to an improved mode of producing a screw-thread on articles molded from paper-pulp or any plastic material of a similar nature; and it consists in placing within the mold, at the point where it is desired to impress the thread upon the article, a perforated, flexible, elastic band having a screw-thread projecting from or grooved into its inner side, so that when the mold is filled the thread will be impressed upon the outside of the article cast in it, and when the molded article is withdrawn from the mold the band will be Withdrawn with it, and be stripped from it after it leaves the mold, without mai-ring the impressed screw-thread, but leaving it sharp and smooth.

Heretofore two methods of making a screwthread upon pulp articles have been used. One is to employ a hinged or opening mold, and the other to cast thepulp upon a threaded core, which is withdrawn by unscrewing from the ends of the mold. The rst of these modes involves a comparatively expensive mold, and the presence of a burr upon the article on the line where the sides of the mold come together. The last-named method, from the nature of the material, tends to leave the screw-thread ragged and broken.

(No model.)

In the accompanying drawings, A marks the bottom, and B the annular top, of a mold suitable for making the screw-tops of paper vessels from pulp. C is the plunger which compresses the pulp in the mold.. D is the perforated elastic band, which lits exactly into the bottom of the mold, its ends abutting accurately and tightly against each other when inserted. On its inner side isa screw-thread, t, either in relief or intaglio.v

The operation is as follows: The elastic band D having been placed in the mold A in the desired position, the annular cover Bis attached and the mold filled with pulp. The plunger Gis then applied and forced down, driving the pulp against the sides of the mold, which are perforated to allow the escape of water. The screw-thread on band D embeds itself in the plastic pulp, and when the molded article E is Withdrawn from the mold the band D comes out with it and is then stripped off, leaving a sharp and smooth impression of the screw-thread upon the edge ofthe article.

I claim as my invention7 and desire to secure by Letters Patentl. The combination, with a mold for manufacturingY articles from paper-pulp, of a removable perforated elastic band having a screw-thread on its inner side, and capable of being withdrawn with the molded article and subsequently stripped from it, all substantially in the manner and for the purpose set forth.

2. The combination, with a pulp-mold, of a removable perforated elastic band sprung in against the inside Walls of the Inold, with its ends abutting closely against each other, as described.

3. A barrel-head or similar article made from paper-pulp, and having a screw-thread impressed upon it during manufacture, in a mold provided with a close and immovable bottom, all as set forth.

In testimony that I claim the foregoing as `my own invention I affix my signature in presence of two witnesses.

GARRETT F. SPEER.

Witnesses GEO. F. GRAHAM, GHAs. F. STANSBURY. 

